Increases in the amounts and types of hazardous waste materials have spurred real concerns about the destruction of the environment and potential risks to life. Factories, foundries and other industrial complexes typically produce large quantities of solid waste containing heavy metals such as lead, cadmium and zinc as well as other garbage and debris. As a result, new and improved ways of handling, transporting and safely disposing of such materials are needed to help reduce the ecological and health risks associated with hazardous wastes.
While, inland and offshore landfills can be used to bury and dispose of most solid waste, a landfill that was once considered safe and distant can, over time, pose serious health and ecological risks. First, leachable heavy metals such as lead, cadmium, copper and zinc are often mixed in with other waste material. Over time, these substances contaminate and pollute the surrounding environment.
Second, the expense of handling and transporting waste materials can be high since hazardous waste usually must be transported long distances to approved disposal facilities or disposed of in costly incinerators.
Additionally, landfill materials and the existing soil conditions of a particular landfill area vary greatly depending on the geographic site and local industries that utilize a particular site. This results in wide variations in the type of waste materials and the treatment methodology employed. In particular large percentages of rock, granite and hard clay soils interfere with the ability to achieve a stable, uniformly nonleachable material that is easily disposed after treatment. The present invention, however, alleviates these concerns.
Prior methods available for treating hazardous waste include U.S. Letters Pat. No. 5,037,479 which discloses a process for chemically treating solid wastes containing unacceptable levels of leachable metals, such as lead, cadmium and zinc to control leaching under both acidic and non-acidic conditions. The '479 patent teaches a method of mixing a solid waste with at least two additives, such as a pH buffering agent and an acid or salt, to convert the leachable metal into non-leachable form.
Additionally, U.S. Letters Pat. No. 4,124,405 discloses a method of treating wastes in the form of liquids and aqueous sludge and converting such wastes into a solid material.
Further, U.S. Letters Pat. No. 3,837,872 discloses a method of mixing an aqueous solution with waste material causing a reaction that produces a chemically and physically solid product fit for disposal.
While these prior methods can be used to treat hazardous waste and convert or transform it to a less hazardous material, the results achieved by using these prior methods varied depending on the size, weight, composition and dimension of the waste product. Thus, prior methods did not take into account larger sized materials which are more resilient to a given chemical treatment and require longer exposure to the additives for effective treatment.
Until the present invention, there was no way of separating and reducing in size the larger sized materials from other wastes prior to the chemical treatment process. Removal and reduction in size of such materials allows the waste to be more evenly and uniformly treated. This results is an end product that is easier and safer to dispose and easier to transport to an approved disposal facility.
Furthermore, while the prior methods used chemical additives to convert hazardous products into a nonhazardous form, these prior methods did not effectively disperse the chemical additive throughout the entire waste surface area. Unlike the present invention, prior methods did not regulate the size of the waste substance prior to treatment in order to insure that the entire substance is immersed with the chemical additive thus providing for a more thorough treatment process.
Accordingly, it is one aspect of the present invention to provide for an apparatus and method of reducing the size of waste materials to allow for a chemical treatment process that evenly and uniformly treats the waste.
Another aspect of the present invention is its ability to regulate the size of the waste prior to chemical treatment. In accordance with this aspect of the present invention, a series of hammer-like devices are used to break-up the waste into smaller sized portions. Due to their smaller size, these portions will more readily and effectively bond to the chemical additive used during the treatment process resulting in a more effective treatment.
Yet another aspect of the present invention is its ability to cycle waste material through the treatment process as many times as necessary to ensure a uniform and consistent disposable end substance. In accordance with this aspect, vibrating screen type filters are used to extract matter which has not been sufficiently processed through the size reduction phase of the present invention. The extracted matter is then recycled via a recycling unit for further treatment or disposal.
Yet another aspect of the present invention is to produce a manageable nonhazardous substance fit for disposal in situ or transportation to suitable disposal facilities. In accordance with this aspect of the invention, concrete or another similar binding additive is combined with the filtered and broken up waste material and then milled into a fine granular substance. The substance may then be safely disposed of in situ or transported to another location.